Hot liquid metal pumps



- June 14, 1966 J. A. GEHRM 3,255,702

HOT LIQUID METAL PUMPS Filed Feb. 27, 1964 5 Sheets-Sheet 1 I i a! 40 g'f 1 1 t- 36 I 46 I if 44 I 6'0 14 a I go 23/i F 34 a i} a; l V

John A. Gehrrn/ INVENTOR- F/TTORNEy June 14, 1966 G R 3,255,702

HOT LIQUID METAL PUMPS .7722272 A. GeZzrm/ INVENTOR.

HTTORWEY June 14, 1966 J. A. GEHRM 3,255,702

HOT LIQUID METAL PUMPS Filed Feb. 2?, 1964 5 Sheets-Sheet a John 1?Gehrm INVENTOR,

J. A. GEHRM HOT LIQUID METAL PUMPS June 14, 1966 5 Sheets-Sheet 5 FiledFeb. 27, 1964 5 INVENTOR.

BY 'YV. fix/Md A 7' 70 kW 5 1 United States Patent 0 3,255,702 HOTLIQUID METAL PUMPS John A. Gehrm, Gettysburg, Pa., assignor to MoltenMetal Systems, Inc., a corporation of New Jersey Filed Feb. 27, 1964,Ser. No. 347,925

3 Claims. (Cl. 103-114) This invention relates to improvements in pumpsintended for use in lifting, moving, transferring and circulating moltenand fluid metals, chemicals, salts and other materials, whether hot orcold, which are dilficult, hazardous and corrosive.

Pumps designed for the pumping of molten metal or other molten materialsare of necessity constructed of ceramic or other refractory materialswhich are of brittle character and subject to'rupture under severestresses, such, for example, as those caused by unequal thermalexpansion and contraction of rigidly connected ceramic parts, asin apump having two or more elongated ceramic tubes rigidly connecting anelevated mounting plate for an impeller motor with the impeller housingwhich is immersed in and conveying hot metal from a melting furnace orother receptacle through one of the connecting tubes or pipes. Thestresses on the other parts of the pump resulting from the greaterthermal expansion of the pipe conducting the molten material willultimately cause a rupture in some part or joint of the pump structureand thus totally destroy its usefulness.

Therefore, one of the principal objects of the present invention is toprovide a molten metal pump of refractory material in which injuriousstresses on the component parts and the consequent self-destruction ofthe pump are positively precluded. An important feature of constructionby which this advantageous result is accomplished resides in rigidlyconnecting the mounting plate for the motor to the impeller housing bymeans of only a single pipe or supporting member and leaving the otherpipe or members of the pump unit free for independent longitudinalthermal expansion without affecting other parts of the pump structure.The mounting plate is .provided with means for freely suspending it,together with the impeller shaft and housing from an overhead support,so that the bottom of the housing can be spaced in any desired planeabove the floor of the furnace or other receptacle from which the moltenmaterial is pumped.

Another, and important object of this invention is to provide the pipesof the pump which conduct, or are immersed in, the liquid being pumpedwith relatively thin, insertable and removable tubular liners made ofsemisoft, compressible and non-wetting material which is highlyresist-ant to normal wear, stress and adhesiveness under conditions ofheat and corrosive tendencies from the liquid to which they are exposed,irrespective of whether the liquid is hot or cold. These liners not onlycompensate for the thermal expansion of the pipe, or pipes, but theyalso resist the corrosive action and high heat conditions and alsominimize the abrasive wear and chemical reactions exerted by moltenmetal in the pipes, and also, due to their elasticity andcompressability'the liners absorb shock, protect the pipes and permiteasy and inexpensive repairs by simple replacement of the liners insteadof the pipes. The pipe or 'riser through which molten material is pumpedis preferably provided with a pair of liner sections of the materialreferred to in telescopic but leak-proof relation to permit theirindependent thermal expansion and also to permit the lower section ofthe liner to be withdrawn from the riser pipe with metal or other moltenmaterial which may have been allowed to freeze or solidify therein,after which a new section can be inserted in the riser. Notwithstandingthe protection atforded by the tubular liners referred to the riser pipeas well as any other pipe con nected with the impeller housing ispreferably made of high heat resistant material.

In my improved pump all joints between connected parts are sealed with amaterial of sufficient resiliency to withstand the maximum thermalexpansion and still maintain the strength necessary to prevent therupture or failure of the joints under stresses to which they aresubjected.

In my improved pump the impeller shaft extending from the elevated motorto the impeller in the impeller housing may be incased with the samematerial as that of the liners referred to, especially if the shaft ismade of metal; or the shaft may be made of a material or a combinationof materials which resists the corrosive action of the fluid materialand the conditions of heat prevailing. The shaft may be housed in avertical pipe to which the mounting plate is rigidly attached, orpartially housed in a pipe stopping short of the mounting plate, inwhich case the mounting plate may be attached to the riser through whichthe liquid material is pumped, or to a separate single supporting columnrigidly connected at its lower end to the impeller housing.

All parts of my improved pump that are immersed in or contain liquidmetal are made of a material which will resist corrosive action of themetal being pumped and have sufficient strength at the temperaturesinvolved to perform the pumping action and convey the materials beingpumped. Each of the parts, orin combination, is of a material or designthat will allow each to move within or in relation to othersindependently or individually according to the thermal expansion. Themounting plate or frame is kept out of the molten material at a distancesafely beyond the reach and out of the heat to prevent itsdeterioration. The impeller housing is so designed as to have uniformdimensional stability achieved by choice of materials and/ orcombination of materials sized to present units of equal thickness, soas to prevent unequal stress and expansion due to heat, Wear and weight.The materials of construction are of improved characteristics and designso that it has ample strength to allow for torque and resiliency to theshocks of starting and speed of rotation in the spinning of the impellerat a rate to centrifugally force the molten metal or other material upthrough and out of the riser or discharge pipe. Openings for theadmission of liquid to be pumped into the impeller housing may beprovided in the bottom, or the top of the housing with the impellerinstalled in reverse relation; or the openings may be in the side of thehousing, irrespective of the arrangement of the impeller.

Further objects and advantages of my improved pump will appear or bepointed out in the following specification in which reference isdirected to the accompanying drawings forming a part thereof, and inwhich:

FIG. 1 is a perspective view of one form of molten metal pump inaccordance with my invention;

FIG. 2 is an elevational sectional view of the pump shown in FIG. 1;

FIG. 3 is a top plan view of the pump shown in FIGS. 1 and 2;

FIG. 4 is a sectional view taken on the line 4-4 of FIG. 2;

FIG. 5 is a sectional view taken on the line 5-5 of FIG. 2;

FIG. 6 is a side elevation showing a modification of the pump shown inthe previous views;

FIG. 7 is a top plan sectional view taken on the line 77 of FIG. 8,showing the impeller housing provided with openings for admission ofliquid through its top wall instead of its bottom wall;

FIG. 8 is a section taken on the line 8-8 of FIG. 7, showing theimpeller installed in inverted relation to its arrangement as shown inFIG. 2;

FIG. 9 is a top plan section taken on the line 99 of FIG. 10 showing theimpeller housing provided with openings for admission of liquid throughits side wall instead of its top or bottom wall; and

FIG. 10 is a section taken on the line 1010 of FIG. 9.

Referring to the drawings in which like numerals designate like parts inthe several views, and referring first to FIGS. 1 to 5, my improved pumpis designated generally by the numeral 10, and the specific formillustrated in the views referred to includes an impeller housing 12having parallel top and bottom walls and a vertically spaced mountingplate 14. This housing has a large circular opening 16 in its bottomwall and has a through opening in its top wall defining an inwardlyfacing frustoconical recess or seat 18 merging upwardly at its reducedend into a short straight bore 20. Through the opening 16 and the bore20 is inserted an elongated pipe 22 having on its lower end an upwardlytapered flange 24 of a shape and size to fit within the seat 18, butwith a narrow surrounding space to receive a filling of a material 26 ofa character which attaches and seals the pipe 22 to the housing 12, andhas sufficient resiliency to permit a substantial degree of thermalexpansion of the attached parts without danger of rupture of the jointor seal.

The pipe 22 is attached at its upper end to the mounting plate 14through a two-part clamp 28 carried by the mounting plate and held inclamping relation by bolts or studs 30 and nuts 32, shown more clearlyin FIG. 4, with an insulating liner 34 between the clamp and pipe.However, it should be understood that various other suitable means forattaching the pipe or other support to the mounting plate may besubstituted.

A vertical support 36 is mounted on the mounting plate and a motor 38(which may be of electrical, air or hydraulic type) is attached to thevertical support through a lateral bracket 40, or other suitable means,with the shaft 42 of the motor in concentric relation with the pipe 22.An impeller shaft 44 is detachably connected to the motor shaft througha suitable coupling 46 and extends through the pipe 22 into the impellerhousing 12 where it is rigidly attached to a horizontal rotary impeller48 by suitable means, the impeller and shaft being insertable andremovable through the opening 16, which is of a greater diameter thanthat of the impeller. In the specific form of my invention illustratedin FIGS. 1 to 5 the shaft 44 is inclosed throughout the greater portionof its length within a thin casing 52 made of non-wetting, resilient,high heat and corrosion resistant material with a gasket 54 of similarmaterial interposed between the lower end of the tube 46 and the top ofthe impeller housing 12. A tube or liner 56 of similar material isremovably inserted in the pipe 22 throughout its length as a replaceablemeans of protection of the inner wall of the pipe. However, the shaft 44and the pipe 22 may be made of a material having the characteristicsmentioned so that the tube 46 and the tubular liner 50 may be omitted.The impeller housing 12 and the impeller 48 are made of ceramic or othersuitable refractory material.

The impeller housing merges at one side into a reduced portion 12containing a liquid outlet chamber 58 in open lateral communication withthe interior of the impeller housing containing the impeller 48. Avertical recess 60 is formed in the top wall of the portion 12 and acentral reduced bore 62 extends from the recess 60 entirely through theportion 12 to receive a liner section 64 inserted within a second pipeor riser 66 of a slightly lesser diameter than that of the recess 60 andthe lower end of which is seated in the recess and anchored therein bymeans of heat resistant resilient sealing material 68 in the spacebetween the wall of the recess and the riser 66, which may be providedwith an annular groove 70 to receive the sealing material to form asealed joint. The lower end of the bore 62 is slightly enlarged toreceive a refractory plug 72 against which the lower end of the tubularliner 64 rests to hold it within the riser 66. This plug is firmlyanchored in the recess of the bore by means of sealing material 74, butmay be forcibly withdrawn for replacement of the tubular liner, orremoval of any frozen material or other obstruction. The tubular liner64 has a large lateral opening 65 at its bottom end in communicationwith the impeller chamher.

The upper end of the riser 66 terminates in a downwardly tapered flange76 similar to the flange 24 of the pipe 22 and this flange 76 isinclosed by, but slightly spaced from, a frusto-conical recess 78 formedin a collar 80 welded to or otherwise rigidly attached to the mountingplate 14, so that the riser 66 is left free for thermal expansionthrough an opening 82 in the mounting plate in concentric relation withthe recess 78 without exerting any stress on either the mounting plate,riser, impeller housing or other parts of the pump structure. With thisarrangement the impeller housing 12, the riser pipe 66 and all partscarried by them are attached to the mounting plate by a single support,which in the form illustrated is the pipe 22. However, a will later beexplained the riser 66 or some other element may be utilized as thesingle supporting member, if desired.

Welded or otherwise rigidly attached to the upper end of the collar 80is a cylindrical extension fitting 84 internally threaded at its upperend and connected to the externally threaded end of a reducing sleeve86. This extension fitting 84 has a short bore 85 below its internalthreads of a slightly larger diameter than that of flange 76, which notonly allows lateral expansion of the flange but also allows pipe 66 toexpand longitudinally without stress on any part of the pump unit. Theinternally threaded end of the extension fitting 84 is connected to thelarger externally threaded end of a reducing sleeve 86. The externallythreaded reduced end of the sleeve 86 is connected to a doubleinternally threaded coupling 88, the outer end of which i connected tothe end of a pipe extension 90. The reduced internal diameter of thesleeve 86 is slightly greater than that of the tubular liner section 64,the end of which terminates within the larger diameter of the sleeve.Within the reduced portion of the sleeve 86 is a short tubular linersection 92 of the same material, and fitting over the upper end of theliner section 64 in telescopic but leak-proof relation therewith, topermit independent thermal expansion of the liner sections. Abutting theliner section 92 is a series of segmental sections 94 in the curvedportion of the elbow pipe section 90, the outer one of which is abuttedby a horizontal liner section 96. However, a single liner sectioncorresponding to all the separate sections 92, 94 and 96 can bemanufactured as asingle unit.

The mounting plate 14 is provided with supporting cables 98 or othersuitable means, through which it is suspended from an overhead support(not shown), with the impeller housing in any desired plane above thefloor of the furnace or other container 100 of the molten metal or otherliquid material to be pumped.

In operation the impeller 48, driven by the motor 38, centrifugallyforces the liquid 102 in the container 100 through opening 65 andthrough the riser 66 and extensions to the desired point of delivery.Since the mounting plate 14 and impeller housing 12 are connectedtogether in spaced relation only by the pipe 22 the riser pipe 66 canfreely move longitudinally through the opening 82 in the mounting plateand the bore 85 in the extension 84, as well as expand laterallytherein; and the liners through which hot metal or material is pumpedare free for telescopic independent movement. None of the parts of thepump are subject to stress due to thermal expansion of any of the otherparts. Therefore, all possibility of self-destruction of the pump ispositively precluded.

As previously mentioned, it molten metal or other material is allowed tosolidify in the tubular liner section 64 it can be withdrawn from theriser upon withdrawal of the plug 72 and replaced with a new liner. Alsothe tubular liner in pipe 22 can be withdrawn and replaced by detachingthe pipe from the clamp 28.

From the foregoing description it will be seen that the entire pumpassembly is supported solely by the pipe 22 with the mounting plate andmotor at a sufiicient distance above the hot metal supply to prevent anydamage from the heat. In addition to the function of the tubular liners56 and 64 in protecting the pipes 22 and 66 against corrosive action ofthe hot liquid being pumped the liners serve as insulators against thetransfer of excessixe heat to the pipes. Also the casing 52 protects theshaft 44 against excessive heat damage and corrosive action from hotmetal or material. Thermal longitudinal expansion and contraction ofpipe 22 affect only the spacing of the mounting plate and impellerhousing without stress on either or other parts of the pump. Thermalexpansion and contraction of riser 66 afiects no part of the pumpstructure, since it can move freely through the opening 82 in themounting plate and the bore 85 in the extension 84.

In FIG. 6 is shown a modified form of my improved pump in which theriser pipe 66, through which the hot metal or. the like is conducted, isutilized as the single support for supporting the impeller housing 12 onthe mounting plate 14 in parallel spaced relation. In this embodiment ofmy invention the clamp 28, or other suitable clamping means, carried bythe mounting plate is applied to the riser pipe 66, instead of the pipe22, or other support, so that the mounting plate is attached to the pipe66. The pipe 22' may then be shortened, as illustrated, so that it hasno contact with the mounting plate. The construction of the short pipe22 may be identical with the lower portion of the pipe 22, and its meansof attachment to the impeller housing 12 may also be the same, as shownin FIG. 2. This shorter pipe serves the same purpose as the pipe 22 ineliminating the necessity for a packing between the housing and theshaft 52, the pipe 22 being of sufficient heightto preclude thesplashing from its top of molten metal agitated by the impeller 48.,This still maintains the concept and principle of connecting theimpeller housing to the mounting plate in distantly spaced relation bymeans of a single support, thus permitting movement of the housingtoward and from the mounting plate without exerting the least stress onany other parts of the pump unit.

From the foregoing description it will be seen that the impeller housingmay be connected to the mounting plate in spaced relation by singlesupport entirely separate from either of the pipes 22 and 66.

In the form of my invention shown in FIGS. 7 and 8 the impeller housing12a is provided with openings 104 in its top wall for admission ofliquid into the housing, and the impeller 48 in installed in the housingin inverted relation to its arrangement shown in the previous views.Otherwise the construction of the entire unit may be the same as shownin FIGS. 1 to 5 or in FIG. 6.

In the form of my invention shown in FIGS. 9 and 10 the impeller housing12b is provided with openings 106 in its side wall for admission ofliquid into the housing. In this embodiment the impeller 48 may beinstalled either in the inverted arrangement shown in FIG. 8 or as shownin FIG. 2.

It is essential that the total liquid capacity of the openings 104 shownin FIGS; 7 and 8 be, at least, equal to the discharge capacity of thepipe 66. The same essential applies to the openings 106 shown in FIGS. 9and 10. The impeller shown in FIGS. 7 to 10 may be identical with thatshown in FIG. 2, except installed in the housing in inverted relation,which does not impair its pumping efliciency.

In each of the forms of my improved pump illustrated the impellerhousing has a circular opening 16 in its bottom wall of sufficientdiameter to permit the insertion and removal therethrough of theimpeller 48, and in the form shown in FIGS. 1 to 5 this opening isutilized for admitting liquid to be pumped into the impeller housing,

thereby dispensing with the necessity of having otherliqu-id inletopenings in the housing.

In the pump structures shown in FIGS. 7 to 10 it would be possible tosubstitute a single elongated opening for the several smaller openingsin the top and side walls as shown.

Obviously, various other changes or modificationsin my improved pump maybe made within the spirit and scope of my invention. Therefore, itshould be understood that the embodiments of my invention shown anddescribed are intended to be illustrative only, and restricted only bythe appended claims.

I claim:

1. A pump of the class'described comprising, in combination, a mountingplate, an impeller housing having top and bottom walls vertically spacedby a vertical wall and having, at least, one liquid inlet opening in oneof its walls and a liquid outlet opening in its vertical wall, acentrifugal impeller in said housing in parallel relation -.with its topand bottom walls, the bottom wall of said housing having an openingtherein of a sutficient diameter to permit the passage therethrough ofsaid impeller, a single elongated member attached at its ends to saidmounting plate and impeller housing for supporting said housing on saidplate in distantly spaced relation therewith; a motor mounted on saidplate and having a shaft connected with said impeller; means connectedwith said plate for suspending it and said housing in a horizontalposition above a floor; said impeller housing having a through verticalbore in communication with the liquid outlet opening therein, aremovable plug in the bottom end of said opening, a circular recess inthe top of said impeller housing surrounding the vertical bore therein,a liquid discharge pipe sealed at its bottom end in said recess andterminating at its upper end in a downwardly tapered flange immediatelyabove said mounting plate, said mounting plate having therein a guideopening through which said pipe projects; a cylindrical extensionfitting attached to said mounting plate in concentric relation with saidguide opening, said extension fitting having therein an upwardly taperedopening and a bore extending upwardly from said tapered opening andinclosing-the flanged end of said discharge pipe; the guide opening inthe mounting plate, the upwardly tapered seat and the bore in saidextension fitting each being of a sufficient diameter to allow freelongitudinal and lateral expansion therein of said flanged dischargepipe; and a liquid discharge pipe extension connected to the outer endof said extension fitting.

2. A pump as in claim 1 in which the liquid discharge pipe is providedwith an insertable and removable liner section of refractory andcorrosion resistant material extending from the removable plug in thebottom wall of the impeller housing to a plane above said extensionfitting, said liner having an opening at its lower end in communicationwith the liquid outlet opening in the housing; and another liner sectionof like material inclosing the 7 8 outer end portion of the first linersection in telescopic 2,732,809 1/1956 Mattingly et a1 103-114 andleak-proof relation therewith. 2,948,524 8/1960 Sweeney et a1 103-103 3.A pump as in claim 2 in which said liner sections are 3,010,402 11/1961King 103-111 of resilient, refractory and corrosion resistant material.3,048,384 8/ 1962 Sweeney et al. 103-103 5 3,131,637 5/1964 Jennings103-103 References Cited by the Examiner FOREIGN PATENTS UNITED STATESPATENTS 1,238,364 7/1960 France.

2,181,973 12/1939 Jasberg 103 114 2,304,849 12/ 1942 Ruthman 103111SAMUEL LEVINE, Primary Examiner. 2,381,824 8/1945 La Bour "103-114 102,528,210 10/1950 Stewart 103 114 HENRY F-RADUAZQEmmim-

1. A PUMP OF THE CLASS DESCRIBED COMPRISING, IN COMBINATION, A MOUNTINGPLATE, AN IMPELLER HOUSING HAVING TOP AND BOTTOM WALLS VERTICALLY SPACEDBY A VERTICAL WALL AND HAVING, AT LEAST, ONE LIQUID INLET OPENING IN ONEOF ITS WALLS AND A LIQUID OUTLET OPENING IN ITS VERTICAL WALL, ACENTRIFUGAL IMPELLER IN SAID HOUSING IN PARALLEL RELATION WITH ITS TOPAND BOTTOM WALLS, THE BOTTOM WALL OF SAID HOUSING HAVING AN OPENINGTHEREIN OF A SUFFICIENT DIAMETER TO PERMIT THE PASSAGE THERETHROUGH OFSAID IMPELLER, A SINGLE ELONGATED MEMBER ATTACHED AT ITS ENDS TO SAIDMOUNTING PLATE AND IMPELLER HOUSING FOR SUPPORTING SAID HOUSING ON SAIDPLATE IN DISTANTLY SPACED RELATION THEREWITH; A MOTOR MOUNTED ON SAIDPLATE AND HAVING A SHAFT CONNECTED WITH SAID IMPELLER; MEANS CONNECTEDWITH SAID PLATE FOR SUSPENDING IT AND SAID HOUSING IN A HORIZONTALPOSITION ABOVE A FLOOR; SAID IMPELLER HOUSING HAVING A THROUGH VERTICALBORE IN COMMUNICATION WITH THE LIQUID OUTLET OPENING THEREIN, AREMOVABLE PLUG IN THE BOTTOM END OF SAID OPENING, A CIRCULAR RECESS INTHE TOP OF SAID IMPELLER HOUSING SURROUNDING THE VERTICAL BORE THEREIN,A LIQUID DISCHARGE PIPE SEALED AT ITS BOTTOM END IN SAID RECESS ANDTERMINATING AT ITS UPPER END IN A DOWNWARDLY TAPERED FLANGE IMMEDIATELYABOVE SAID MOUNTING PLATE, SAID MOUNTING PLATE HAVING THEREIN A GUIDEOPENING THROUGH WHICH SAID PIPE PROJECTS; A CYLINDRICAL EXTENSIONFITTING ATTACHED TO SAID MOUNTING PLATE IN CONCENTRIC RELATION WITH SAIDGUIDE OPENING, SAID EXTENSION FITTING